Scientists might not be able to travel inside an erupting volcano, to the bottom of the ocean, or across the solar system. But they can learn about the conditions in these places from rocks they collect.

Rocks also give scientists a look back in time. We know about life long ago from the fossils held in sedimentary rocks. Fossils tell us when, where, and how ancient plants and animals once lived on the Earth.

Rocks can also tell us about the history of Earth itself. They hold clues to how the Earth formed and how it's changed over billions of years.